How big are the stock tail pipes and how restrictive are they?
 

On say my 96 mustang gt the stock tail pipes from the muffler to the rear bumper are 2.25 in. right? If not then they must be 2.5in. cause I think the ones on the 96 cobra appear to be bigger. Also how restrictive are they i.e. I'm sure everyone noticed the huge crimp in the pipes near the gas-tank like someone pinched it in the vice, why is that? Cause my tailpipes have seen better days and I would like then to match the size of my H-pipe and mufflers and the H-pipe is 2.5 in. and I dont like that pinch in the pipe too much and mac sells new ones for like $179 I think, thanks for any input

2 1/4". I wouldnt say that they are really restrictive, but you can get somewhat of a better flow going with an aftermarket catback. Alot of it has to do with the mandrel bends in the aftermarket systems as opposed to the style of bends (almost collapsing on the I.D. of the bend) that comes with the stock tubing. The size just opens the flow up that much more. Also, if you are running any type of forced induction, the need for a larger, better flowing exhaust becomes more apparent.


The "crimps" come from the pipe bending machine. It is like a pressed bend. I cant remember the name of the type of machine. But it is not from a vise.

As long as they are not the smallest pipe in the exhaust, there is no restriction. If your collectors, mid pipe and mufflers are all bigger, go for it.

I would personally make sure the muffs are a flow-through, like magnaflow or ultraflow first, since a chamber is going to create backpressure worse than a .25 decrease in diamiter.

I just dumped mine(dumped magnaflow muffs) flows better and you drop weight as well

I would like dumps but I like seein the dual exhaust stickin out the rear bumper, hehe and yea i have 2 chamber flows and if I get the mac 2.5 inch replacement exhaust pipes those will weld right up to my 2 chamber flows right?